The present invention is related to apparatus for separating successive groups of articles from an upright stack so they may drop gravitationally therefrom; and more particularly to such apparatus utilized for articles having reduced upper ends and enlarged lower ends and wherein the articles are arranged in an upright stack with the reduced ends of one set of articles nesting in the enlarged ends of the next successive group of articles.
Most bottles, cans and packages are placed in paperboard or cardboard containers for shipping. These cartons ae three-dimensional rectangular enclosures which have a top, bottom, two sides and two ends. Most cylindrical articles such as cans and bottles are placed upright in the cartons and in one or two layers with or without dividers positioned between the layers. The size, weight, and number of the articles generally determine the most economical arrangement and shape of the carton enclosure. Generally, articles are packed in multiples of six with 24 being the most popular size. A carton containing 24 articles is frequently referred to as a "case" and a carton containing 12 articles is generally referred to as a "half-case." This terminology is most commonly used in the beverage and canned goods industry. A case of 24 bottles or cans is generally arranged in a single layer of four files and six ranks. A "half-case" is generally arranged in three files with four cans or bottles in each, and four ranks with three cans or bottles each.
In loading the articles into the cases or cartons, a case packing machine is generally utilized to separate in successive groups the prescribed numbers of articles, usually 6, 12, or 24, from a stack. The machine then automatically places each group of articles within a case or container supplied by conveyor. Usually, the bottles or cans are forced horizontally into a container having a side opening. With the bottles or cans entering in a horizontal relationship, it follows that a substantial amount of floor space will be occupied by the article-handling mechanisms that feed rows of articles horizontally toward the waiting containers. It has therefor become desirable to re-orient the in-feed of bottles or cans so they will take up less floor space. This is done by arranging the entering rows of articles vertically.
Development of new plastic containers has caused some difficulty with the vertical feeding machines in that the ordinarily reliable escapement mechanisms utilized therewith do not handle the containers gently enough to prevent article damage.
An example of a previously preferred form of escapement mechanism is disclosed in United States Patent Application Ser. No. 458,106 filed Apr. 5, 1974, and commonly assigned with the present application. This device makes use of an escapement mechanism whereby the entire upright weight of an article stack is allowed to successively drop onto a stationary surface from a height equal or slightly greater than the overall height of a single article. Although this escapement mechanism is very effective, it can damage articles that are fragile by nature. The development of thinner plastic beverage containers has necessitated the replacement of the above described escapement mechanism with another by which the articles are handled more gently.
The present invention is concerned with an escapement mechanism by which vertically stacked articles may be successively released in prescribed groups without allowing the vertical stack to be abruptly dropped onto a stop mechanism. This is accomplished by providing a vertically moveable stop mechanism that engages successive groups of articles and gently lowers them along with the entire stack to a retractable support mechanism. The stop mechanism is further designed to return to a first elevation after delivering a group of articles to the retractable support mechanism so that the stack of articles may be gently lifted from engagement with the group of articles presently resting on the support mechanism. The only downward force on the retractable support is the weight of the group itself rather than the entire weight of the vertical stack of articles. With the remainder of the stack supported by the stop mechanism, the retractable support may be moved from under the group of articles to allow the articles to fall freely to a transfer mechanism.